The present invention relates generally to pumps. More particularly, the present invention relates to self-priming pump systems.
This invention relates to the field of pumps, and more particularly, to industrial type pumps and related pump components. In many cases a pumping system includes an oil lubricated vacuum pump which is utilized to prime the system. Typically, the oil sump of an oil lubricated vacuum pump must be drained daily to remove water and oil emulsion. In some cases, unscrupulous pump operators do not follow the recommended procedure for disposing of this waste oil, and simply drain this waste oil onto the ground. Even when the proper draining procedure is used, these oil lubricated pumps can be a source of pollution. A fine mist of oil typically is discharged from the oil lubricated vacuum pump. An oil trap may be installed on the oil lubricated vacuum pump in an attempt to reclaim this oil. Even when an oil trap is utilized, however, oil sometimes escapes. The oil lost by an oil lubricated vacuum pump can be one to two cups a day, or 15 quarts per month. This oil is discharged either on the ground as liquid or into the air as a fine mist, both of which are undesirable.
For many applications, the fluid being pumped includes suspended solids such as sand, silt, rocks, rags etc. In these applications a strainer is often coupled to a distal end of the inlet hose to prevent large solids from being drawn into the pump. Suction created at the distal end of the hose during a pumping operation may draw an accumulation of foreign material up against the strainer, causing the strainer to become clogged. When this occurs, a back flushing procedure may be utilized to un-clog the strainer. In a typical back flushing procedure, the head pressure created by the distance between the distal end of the inlet hose and the pump is used to create a reverse flow through the strainer. In some applications, the pump is not a great deal higher than the distal end of the inlet hose. Thus, there is very little head pressure available for a back flushing procedure. Even in cases in which the pump is a good distance higher than the distal end of the inlet hose, the head pressure is sometimes not adequate to unclog the strainer.
The present invention provides a pumping system for pumping water, sewage or other pumped material from one location to another. A pumping system in accordance with one embodiment of the present invention includes a motor coupled to a centrifugal pump for driving the centrifugal pump. The pumping system also includes a separator defining a reservoir in fluid communication with an inlet of the centrifugal pump and an inner tank defining a passageway extending through the reservoir. The passageway is preferably fluidly isolated from the reservoir and thermally coupled to the reservoir.
A water liquid ring vacuum pump is preferably used to prime the pump. The water liquid ring vacuum pump may include an inlet that is in fluid communication with the reservoir of the separator, and thus provides the required vacuum to prime the pump. The vacuum pump also may include a discharge port in fluid communication with the reservoir of the separator, through the inner tank. Water is collected from the discharge of the vacuum pump by the inner tank, and is provided back to the water liquid ring vacuum pump, thereby forming a closed system. In a preferred embodiment, the pumping system includes a first valve interposed between the discharge port of the vacuum pump and the reservoir of the separator, and a second valve between the reservoir of the separator and the inlet of the water liquid ring vacuum pump.
The first valve preferably has a first port in fluid communication with the discharge port of the vacuum pump, a second port in fluid communication with the atmosphere, and a third port in fluid communication with the reservoir of the separator. The second valve preferably has a first port in fluid communication with the inlet of the vacuum pump, a second port in fluid communication with the reservoir of the separator, and a third port in fluid communication with the ambient atmosphere.
During normal operation, the first valve fluidly connects the discharge of the vacuum pump to the atmosphere and the second valve fluidly connects the inlet of the vacuum pump to the reservoir of the separator. During a back flush operation, the first valve fluidly connects the discharge of the vacuum pump to the reservoir of the separator and the second valve fluidly connects the inlet of the vacuum pump to the atmosphere.